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• An ultra-low infrared emissivity composite coating was successfully prepared by a simple method. • Infrared emissivity and glossiness of the composite coating can be as low as 0.053 and 17.3. • The ultra-low infrared emissivity composite coating has outstanding mechanical properties. • The ultra-low infrared emissivity composite coating has good salt water resistance. An ultra-low infrared emissivity composite coating with outstanding mechanical properties and salt water resistance was prepared by using epoxy resin, flake Al powders, KH560 and dioctyl phthalate (DOP) as resin matrix, functional pigments, and modifiers, respectively. The effects of Al powder addition, silane coupling agent types, silane coupling agent addition, and DOP addition on the coating performance were discussed. In addition, the salt water resistance of the coating under the optimal formulation conditions was examined. The results show that when the addition amount of Al powder is 50 wt%, the coating has lowest infrared emissivity (0.025) and glossiness (20.7) properties. By adding a certain amount of KH560 and DOP to the coating formulation, the mechanical properties of the coating can be significantly improved by enhancing the bonding strength between the resin matrix and the pigment, and between the resin matrix and the substrate. When the content of KH560 and DOP in the coating are both 7 wt%, the coating has ultra-low infrared emissivity (0.053), low glossiness (17.3), and outstanding mechanical properties (adhesion strength is grade 1, flexibility is 2 mm, impact strength is 50 kg.cm) at the same time. After the coating with the best formulation was corroded by salt water for 21 days, the emissivity, glossiness, and mechanical properties of the coating had limited changes, which showed that the prepared coating had good salt water resistance. [ABSTRACT FROM AUTHOR]

A novel triethylenetetramine modified graphene oxide/chitosan composite (TGOCS) was successfully synthesized by microwave irradiation (MW) method and compared with one prepared by conventional heating. This composite was characterized by FTIR, XRD, SEM, BET and elemental analysis. Adsorption of Cr(VI) on the composite was studied. The experimental results indicated that the product obtained by MW had higher yield and uptake than one obtained by the conventional and uptake of TGOCS for Cr(VI) was higher than that of the recently reported adsorbents. The effects of various variables on adsorption of Cr(VI) by TGOCS were further researched. The highest adsorption capacity of 219.5 mg g −1 was obtained at pH 2. Adsorption followed pseudo-second-order kinetic model and Langmuir isotherm. The capacity increased as increasing temperature. The adsorbent could be recyclable. These results have important implications for the application expansion of microwave preparation and the design of new effective composites for Cr(VI) removal in effluents. [ABSTRACT FROM AUTHOR]

• Nickel–manganese sulfide grown on Ni foam was developed via a hydrothermal method. • NiMnS@NF possessed outstanding activity and durability in activating PI. • NiMnS@NF can initiate the activation of PI for the NiMnS@NF–PI* formation. • Superoxide radicals played a cooperative role in removal of organic contaminants. • NF's monolithic nature simplified the catalyst recycling process. Nickel–manganese bimetallic sulfide microparticles in situ grown on Ni foam (NiMnS@NF) with controllable morphology and composition were developed via a hydrothermal method to boost potassium periodate activation for oxidation of multiple micropollutants. Benefiting from the unique morphology and structure, along with a synergistic effect of different components, the optimized NiMnS@NF exhibits outstanding performance and durability in potassium periodate activation, surpassing other oxidant systems (e.g., H 2 O 2 , peroxydisulfate, and peroxymonosulfate). Electron spin resonance analysis, scavenging tests, electrochemical analysis, and galvanic oxidation tests unveiled that NiMnS@NF can initiate the activation of potassium periodate, resulting in the formation of high-potential metastable intermediates (NiMnS@NF–potassium periodate*). Additionally, superoxide radical anions play a cooperative role in organic elimination. The experimental results further indicate that the synergy among Mn/Ni and S induces a local charge redistribution, improving electron transfer capability and Mn(II)/Mn(III)/Mn(IV) and Ni(II)/Ni(III) redox reactions. This work proposes a feasible and efficient monolithic catalyst for environmental remediation. [ABSTRACT FROM AUTHOR]

It has been accepted that the formability of a sheet metal with a moderate ductility can be limited by not only localized necking (LN), but also ductile fracture (DF). In this study, a theoretical prediction framework is developed for a comprehensive formability characterization, in which forming limit curves at LN (FLCN) and DF (FLCF) are elaborately correlated by considering strain path evolution. A dual-phase steel material (DP590 sheet metal) is selected with a series of DF and Nakajima tests performed. A newly proposed DF model (uncoupled type) is calibrated by implementing a hybrid experiment-simulation method in line with the DF tests, which are designed to achieve DF under distinct stress states, such as simple shear (SS), uniaxial tension (UT), plane strain tension (PST), and balanced biaxial tension (BBT). The resulting three dimensional (3D) fracture surface demonstrates a good agreement with the tested data. The modified maximum force criterion (MMFC) is selected for the theoretical identification of strain path evolution. The calibrated MMFC results in a FLCN exhibiting a certain level of underestimation as compared to the tested data in the range of positive minor strain. The MMFC is improved (iMMFC) by incorporating with an initial strain path-based function for a higher accuracy in characterizing evolutive strain paths; the resulting FLCN is observed to have a better performance than that of MMFC. Theoretical FLCFs are determined by the integral of ductile damage increment (defined by the DF model calibrated) over each identified strain path from UT to BBT. After considering strain path evolution, different deformation stages are added into the finalized forming limit diagrams including both FLCF and FLCN. It is found that the FLCF based on iMMFC model demonstrates acceptable deviations as compared to all the tested cracking data. Moreover, this FLCF intersects with the corresponding theoretical FLCN as load path approaches from UT to BBT, representing a fracture pattern transition from a LN band-accompanied DF to the one without LN band; this prediction is further validated by experimental observations. The FLCF based on MMFC fails to predict this transition behavior. The current study confirms the presence of a competition between LN-induced failure and DF-induced failure for sheet metals. Moreover, all of these findings advance the insight into the importance of performing a DF prediction aside of a FLCN prediction, especially for the case where a sheet metal with a moderate ductility shows a fracture pattern transition behavior. Image 1 • A resistance function to strain path change is introduced into the MMFC. • A prediction framework for FLCF is proposed with strain path evolution considered. • FLCFs are built with different deformation stages highlighted. • The framework shows a competition between different failure mechanisms. • The experimentally observed fracture pattern transition is successfully predicted. [ABSTRACT FROM AUTHOR]

Abstract: Eu3+-doped β-Ga2O3 nanofibers were fabricated by electrospinning. The influence of Eu3+ concentration on the photoluminescence properties of the obtained nanofibers was investigated. The morphology and structure of β-Ga2O3:Eu3+ were characterized by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and Raman spectra. The diameter of the Eu3+-doped β-Ga2O3 nanofibers was in the range of 180–300nm. When the β-Ga2O3:Eu3+ nanofibers were excited by 325nm wavelength, the main emission peak of the samples was 620nm (5D0→7F2), which corresponded to a typical red emission (5D0→7F j (j =1, 2, 3, 4) intra-4f transitions of Eu3+ ions). In addition, the concentration quench effect and energy transfer mechanism in β-Ga2O3:Eu3+ were also discussed. [Copyright &y& Elsevier]